The present invention relates to a rail fastening device particularly suitable for fastening a long rail to a wooden tie.
In general, a rail is secured to a tie or a roadbed by such a way that a tie plate is placed on the tie or a concrete roadbed, and the rail is placed on the tie plate, which is secured to the tie or the concrete roadbed by means of a screw spike or a dog spike, and the rail is secured to the tie plate by means of a plate spring clip. In this case, such a tie plate as shown in FIG. 1 is generally used. Namely, the tie plate 1 is made of carbon steel and formed into a plate shape having slight unevenness in height as a whole, the central portion thereof being a rail-mounting surface 2.
There are provided, at both end portions of the tie plate 1, bores 3 for receiving screw spikes or dog spikes respectively. The tie plate 1 is adapted to be secured to a tie, not shown, by means of the screw spikes or the dog spikes inserted through the bores 3. In addition, a bore 4 for implanting a bolt, not shown, is provided between the bores 3 at end of the end portions of the tie plate 1. A U-shaped plate spring clip, not shown, held by the bolts implanted in the bores 4 respectively supports the base portion of a rail, now shown, mounted on the rail-mounting surface 2.
When the supporting means for the rail is a tie, the conventional tie plate 1 having such a shape as mentioned above is manufactured so that its width dimension is within that of the tie, and provided to each of the right and left sides of the tie so as to support each of right and left rails. The conventional tie plate 1, however, has the following disadvantages:
(1) Although carbon steel is employed as material, as mentioned above, in order to sufficiently endure the bending moment generated in the tie plate, it needs to increase its weight in proportion to increase in the unit weight of the rail in correspondence with increase in the axle load of trains and passing tonnage on it. Therefore, not only the material cost becomes high, but also a large equipment and a high cost are needed for fabrication to produce the tie plate from a long rolled material, so that the cost-performance rate is rapidly lowered.
(2) Since the ratio of area to weight is large, the working efficiencies and working properties are not good in a series of handling operations, such as fabrication, packing, transportation, storage, laying, removal and the like.
(3) Owing to the basic structure, the function is limited to the known one, so that there are no indications of its future development.